The present invention relates to high frequency loudspeaker horns. More specifically, it relates to separate midrange and high frequency horns combined into a single unified unit.
Recent developments in coaxial and/or extended frequency range compression drivers promote the use of a single horn for loudspeakers, however, such horn drivers tend to be prohibitively expensive. Experience with a horn using the tractrix expansion formula has proven to be a good design choice in that it propagates an extended high frequency response without the tendency to “beam”. The use of a single horn for upper frequency reproduction is preferable to using multiple frequency-divided horn and driver combinations as the single horn application presents a single-point acoustic source to the audience, especially when the driver diaphragms are aligned vertically in relation to each other.
A benefit of using separate drivers is that it allows for a wider range of drivers to be selected by price and performance, providing an economic advantage compared to the limited selection and more expensive presented by the coaxial and/or extended range driver. One drawback to the traditional use of two or more separate horn/driver combinations is that typically little attention is paid to the vertical alignment of the diaphragms of the different driving units such as when both horns are mounted on a singe baffle. The difference in overall horn pathway length due to the difference in frequency ranges of the frequency-limited and/or frequency-divided horns and drivers generally is the cause when such horns are flange mounted on a single baffle. Considering the desirability of the single point-source propagation characteristics presented by wide-range coaxial horn drivers and/or single extended-frequency range drivers used in a single horn, a method that provides an alternative to the requirement of using the more expensive wide-range drivers such as employing separate limited-frequency range drivers that are mounted to a single horn in a “time-aligned” manner would be a viable and more economical approach.
The formulas for determining the tractrix flare rate are well known in the art. The magazine article “The Tractrix Horn Contour”, by Bruce C. Edgar, Speaker Builder magazine, February 1981, and another article by the same author titled “The Edgar Midrange Horn”, Speaker Builder magazine, January 1986, are two examples which have served to rekindle interest in the tractrix flare rate.
It is therefore desirable to produce a wide bandwidth horn device employing a single tractrix midrange horn in combination with a tractrix high frequency horn in a single integrated unit which provides a time-aligned performance characteristic and further promotes a wider selection of potential drivers to be easily and economically realized.